Oil pressure regulator



Feb. .7, 1950 L. D. cAHlLL OIL PRESSURE REGULATOR Filed Nov. l, 1945 ygl.

IIA

INVENTOR.

LYSLE D. CAH/LL VBY ATTORNEY Patented Feb. 7, 1950 OIL PRESSURE REGULATOR Lysle D. Cahill, Shaker Heights, Ohio, asslgnor,

by mesne assignments, to Jack t Heintz Precision Industries, Inc., Cleveland, Ohio, a corporation of Delaware u Application November 1, 1945, Serial No. 626,097

4 Claims. (Cl. 137-153) 'I'his invention relates to pressure regulators and has for a primary object to provide an automatic means for maintaining the pressure constant in an hydraulic system at any desired setting.

A more particular object is to provide an oil pressure regulator for automatically maintaining constant pressure in an hydraulic system such as used in aircraft automatic pilots.

With the foregoing and other objects in view the invention resides in the combination of parts and in the details of construction hereinafter set forth in the following specification and appended claims, certain embodiments thereof being illustrated in the accompanying drawings, in which:

Figure 1 is a cross sectional view of the regulator with a setting that would normally direct about half the pressure fluid to the system and by-pass the other half to the sump;

Figure 2 is similar to Figure 1 except the setting is such that system pressure would be a maximum.

Referring more particularly to the drawings a housing I is shown as having an inlet port 2, a by-pass port 3 and a system port 4. A sliding spool valve 5, having an internal passage 8 is shown held within cylinder 'l of housing I. An

-adjustable threaded plug 8 is provided for varying the tension on spool valve 5 by means of a spring 9. Plug 8 is held in any adjusted position by means of a lock nut Ill. A gasket lI is inserted between nut l and housing l to prevent leakage.

On the opposite side of the spool from plug t is a needle valve l2 which is in alignment with and extends partially into the internal passage it of spool 5. Valve I2 is normally held in an unseated position with respect to a valve seat I3 in -passage E by means of a spring lll which engages a cap l5 on valve I2.

A passage l@ in the housing l diverts a part of the pressure iiuid from port 2 into passages il and It, which direct the flow to the needle valve end of spool E, and to the back of cap l5 on valve I2 respectively. A passage I9 is provided in cylinder l to allow flow into sump port l. Two additional passages and 2| are shown in cylinder 'l leading into ports 3 and 4 respectively.

In operation the regulator is installed in an hydraulic system with the high pressure line connected to inlet port 2, the sump line to by-pass port 3, and the system line to port 4. By making either clockwise or counterclockwise adjustment of plug 8 the system pressure may be either raised or lowered to a desired level. Variations in the pressure of the uid coming in port 2 necessitate a rapid regulating means to maintain that desired level constant.

In Figure 1 assume spool 5 to be in an adjusted position by means of nut 8 for a desired system pressure at port 4. The two end portions of spool 5 are shown as partially covering passages 20 and 2I. A decrease in pressure at intake port 2 would make it necessary for spool 5 to move so as to decrease the opening at passage 20 and to increase the opening at passage 2| in order to maintain a constant pressure at system port l. Constant pressure at port 4 would also be obtainable conversely for an increase in pressure at port 2. Figure 2 represents an extreme condition where the pressure at intake port 2 dropped enough to cause spool 5 to move so as to completely block passage 20 and fully open passage 2l.

Movement of spool 5 is automatically controlled by means of needle valve I2 which moves toward or away from its seat I3 in spool 5 with increasing or decreasing variations in the intake pressure. An increase in pressure is transmitted along passages It and I3 to valve cap I5 and valve I2 will move toward its seat i3. A decrease in pressure is handled by spring It! which always tends to move valve l2 away from seat i3.

Passage-ll is used as a means for transmitting iluid from passage l@ to the valve end of spool 5.

Therefore, when an increase in pressure occurs at intake port 22 valve l2 will move toward seat I@ restricting the opening to passage t of spool t, as shown in Figure 1. A pressure will build up behind the valve end of the spool 5 and the spool will move against spring Q proportional to the increase in pressure, the opening of passage 2l being decreased and the system pressure at port l being maintained constant.

When a decrease in pressure occurs at port 2, valve I2 will move, under actuation by spring It, away from seat I3 enlarging the opening to passage 8, as shown in Figure 2. This allows for a decrease in pressure at the valve end of the spool and spring 9 will move spool 5 proportional to the decrease in pressure, enlarging the opening at passage 2I to maintain the system pressure constant.

A regulator as described and claimed herein is particularly adaptable to aircraft automatic pilot systems where close regulation is required to preport, sliding valve means for controlling simultaneously the amount of now to each of the outlet ports, resilient means responsive to decreases in 'intake pressure for moving said sliding means outlet ports, the intake port leading directly into said cylinder, two passages in the cylinder wall leading to one outlet port, a third passage in the cylinder wall leading to the second outlet port,

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so as to increase the ow to the system port, and decrease the iiow to the by-pass port, said needle valve means being responsive to increases in intake pressure and means for moving the sliding means so as to decrease the flow to the system port and increase the iiow. to the by-pass port and opposed iiuid pressure means and resilient a sliding tubular spool valve with a needle valve seat in one end of its tubular portion located within the cylinder, a springl engaging said valve at one end, a threaded plug engaging the housing for adjusting the tension on said spring, a.

needle valve mounted in the housing axially with means for actuating said needle valve means.

Y 4. In an hydraulic pressure regulator for main- I taining a constant pressure in a system, an inlet port, a by-pass outlet port and a system outlet port, a sliding spool valve for controlling simultaneously the amount of flow to each of the outlet ports, a passage through the center of said respect to the spool valve on the opposite side of said valve from the adjustable plug, pressure responsive means for urging said needle valve into its seat, a spring for normally opposing engagement of said needle valve With its seat in the tubular portion o1' the spool valve, a cap on said spring and said needle valve, a passage in the housing to permit iluid to ilow from the intake port to the needle valve end of the spool, and a second passage to permit fluid to flow from the intake port to the cap on the needle Valve.

2. In an hydraulic pressure regulator for maintaining constant pressure in a system, a sliding spool valve for simultaneously regulating the amount of flow to a system and the amount bypassed in combination with a needle valve and an adjustable spring, said spring and needle valve being mounted axially with respect to but on opposite sides of said spool valve for controlling the position of the sliding spool valve and opposed resilient means and iluid pressure means for actuating said needle valve means.

3. In an hydraulic pressure regulator for maintaining a constant pressure in a system, an inlet port, a by-pass outlet port and a system outlet spool valve, a needle valve seat in one end o! said passage, a needle valve means and opposed uid pressure means and resilient means for actuating said needle valve means for controlling the iiow through the spool passage by moving toward or away from its seat in the passage automatically with lincreases or decreases in intake pressure respectively, and causing increases or decreases REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Ramsbeck D'ec. 28,- 1937 Number 

